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Diffstat (limited to 'lisp/progmodes/json-ts-mode.el')
| -rw-r--r-- | lisp/progmodes/json-ts-mode.el | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/lisp/progmodes/json-ts-mode.el b/lisp/progmodes/json-ts-mode.el new file mode 100644 index 00000000000..101e873cf6e --- /dev/null +++ b/lisp/progmodes/json-ts-mode.el @@ -0,0 +1,171 @@ +;;; json-ts-mode.el --- tree-sitter support for JSON -*- lexical-binding: t; -*- + +;; Copyright (C) 2022 Free Software Foundation, Inc. + +;; Author : Theodor Thornhill <theo@thornhill.no> +;; Maintainer : Theodor Thornhill <theo@thornhill.no> +;; Created : November 2022 +;; Keywords : json languages tree-sitter + +;; This file is part of GNU Emacs. + +;; This program is free software; you can redistribute it and/or modify +;; it under the terms of the GNU General Public License as published by +;; the Free Software Foundation, either version 3 of the License, or +;; (at your option) any later version. + +;; This program is distributed in the hope that it will be useful, +;; but WITHOUT ANY WARRANTY; without even the implied warranty of +;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +;; GNU General Public License for more details. + +;; You should have received a copy of the GNU General Public License +;; along with this program. If not, see <http://www.gnu.org/licenses/>. + + +;;; Commentary: +;; + +;;; Code: + +(require 'treesit) +(require 'rx) + +(declare-function treesit-parser-create "treesit.c") +(declare-function treesit-induce-sparse-tree "treesit.c") +(declare-function treesit-node-start "treesit.c") +(declare-function treesit-node-child-by-field-name "treesit.c") + + +(defcustom json-ts-mode-indent-offset 2 + "Number of spaces for each indentation step in `json-ts-mode'." + :version "29.1" + :type 'integer + :safe 'integerp + :group 'json) + +(defvar json-ts-mode--syntax-table + (let ((table (make-syntax-table))) + ;; Taken from the cc-langs version + (modify-syntax-entry ?_ "_" table) + (modify-syntax-entry ?$ "_" table) + (modify-syntax-entry ?\\ "\\" table) + (modify-syntax-entry ?+ "." table) + (modify-syntax-entry ?- "." table) + (modify-syntax-entry ?= "." table) + (modify-syntax-entry ?% "." table) + (modify-syntax-entry ?< "." table) + (modify-syntax-entry ?> "." table) + (modify-syntax-entry ?& "." table) + (modify-syntax-entry ?| "." table) + (modify-syntax-entry ?` "\"" table) + (modify-syntax-entry ?\240 "." table) + table) + "Syntax table for `json-ts-mode'.") + + +(defvar json-ts--indent-rules + `((json + ((node-is "}") parent-bol 0) + ((node-is ")") parent-bol 0) + ((node-is "]") parent-bol 0) + ((parent-is "object") parent-bol json-ts-mode-indent-offset)))) + +(defvar json-ts-mode--font-lock-settings + (treesit-font-lock-rules + :language 'json + :feature 'bracket + '((["[" "]" "{" "}"]) @font-lock-bracket-face) + :language 'json + :feature 'constant + '([(null) (true) (false)] @font-lock-constant-face) + :language 'json + :feature 'delimiter + '((["," ":"]) @font-lock-delimiter-face) + :language 'json + :feature 'number + '((number) @font-lock-number-face) + :language 'json + :feature 'string + '((string) @font-lock-string-face) + :language 'json + :feature 'escape-sequence + :override t + '((escape_sequence) @font-lock-escape-face) + :language 'json + :feature 'error + :override t + '((ERROR) @font-lock-warning-face)) + "Font-lock settings for JSON.") + +(defun json-ts-mode--imenu-1 (node) + "Helper for `json-ts-mode--imenu'. +Find string representation for NODE and set marker, then recurse +the subtrees." + (let* ((ts-node (car node)) + (subtrees (mapcan #'json-ts-mode--imenu-1 (cdr node))) + (name (when ts-node + (treesit-node-text + (treesit-node-child-by-field-name + ts-node "key") + t))) + (marker (when ts-node + (set-marker (make-marker) + (treesit-node-start ts-node))))) + (cond + ((null ts-node) subtrees) + (subtrees + `((,name ,(cons name marker) ,@subtrees))) + (t + `((,name . ,marker)))))) + +(defun json-ts-mode--imenu () + "Return Imenu alist for the current buffer." + (let* ((node (treesit-buffer-root-node)) + (tree (treesit-induce-sparse-tree + node "pair" nil 1000))) + (json-ts-mode--imenu-1 tree))) + +;;;###autoload +(define-derived-mode json-ts-mode prog-mode "JSON" + "Major mode for editing JSON, powered by tree-sitter." + :group 'json + :syntax-table json-ts-mode--syntax-table + + (unless (treesit-ready-p 'json) + (error "Tree-sitter for JSON isn't available")) + + (treesit-parser-create 'json) + + ;; Comments. + (setq-local comment-start "// ") + (setq-local comment-start-skip "\\(?://+\\|/\\*+\\)\\s *") + (setq-local comment-end "") + + ;; Electric + (setq-local electric-indent-chars + (append "{}():;," electric-indent-chars)) + + ;; Indent. + (setq-local treesit-simple-indent-rules json-ts--indent-rules) + + ;; Navigation. + (setq-local treesit-defun-type-regexp + (rx (or "pair" "object"))) + + ;; Font-lock. + (setq-local treesit-font-lock-settings json-ts-mode--font-lock-settings) + (setq-local treesit-font-lock-feature-list + '((constant number string) + (escape-sequence) + (bracket delimiter error))) + + ;; Imenu. + (setq-local imenu-create-index-function #'json-ts-mode--imenu) + (setq-local which-func-functions nil) ;; Piggyback on imenu + + (treesit-major-mode-setup)) + +(provide 'json-ts-mode) + +;;; json-ts-mode.el ends here |